種々の組織学的悪性度の星細胞腫におけるNucleolar Organizer Regionsの解析

The Analysis of Nucleolar Organizer Regions of Astrocytomas with Various Histologic Malignancies

　Nucleolar organizer regions（NORs）はribosomal RNAをコードするDNAループある。このNORsは最近改良されたコロイド銀染色法により容易に観察することができる（AgNOR）。

　私どもは星細胞腫の悪性度とのこのAgNORとの関係を評価するため，星細胞腫7例，退形成星細胞腫9例，神経膠芽腫11例について細胞1個あたりのAgNOR数の平均値，標準偏差を求め，さらにヒストグラムを作成し検討した。その結果，星細胞腫，退形成星細胞腫，神経膠芽腫と悪性度が増加するに従って，AgNOR数の平均値は1.68，1.85，2.76と増加し，AgNOR数の標準偏差も1.87，1.03，1.26と有意に増加した。これに伴いヒストグラムの概観も平坦化した。

　以上の結果よりAgNOR数およびそのばらつきの増加は星細胞腫細胞の正常細胞からの逸脱の程度を反映していると考えられた。

Nucleolar organizer regions (NORs) correspond to the loops of DNA which encode the riobsomal RNA. Acid proteins related to NORs can be stained by the silver colloidal technique (AgNORs). Since the configulations of AgNORs may be related to the protein metabolism or the proliferative activity of the cell, we tried to evaluate the corelationship between the morphology of AgNOR and the his-tologic malignancy in astrocytic tumors. For the quantitative evaluation the histographic pattern of AgNORs was analysed.

Twentyseven surgical specimens of astrocytomas (astrocytoma ; 7 Cases, anaplastic astrocytoma ; 9 cases, glioblastoma ; 11 cases) were examined. The average of the means of AgNOR count in ast-rocytoma, anaplastic astrocytoma, glioblastoma were 1.68, 1.85 and 2.76 resrectively. The averages of standard deviations (S. D.) of AgNOR count were 0.87, 1.03 and 1.26, respectively.

In those tumors, the AgNOR histograms were flattered and the means and S. D. increasd signifi-cantly as the malignancy increased.

We speculate that the increased number and variations of AgNOR count could be a reflection of phenotypic alterlations of astrocytoma cells such as cellular anaplasia and pleomorphism.